Fluid dispensing valve with a spring plate

ABSTRACT

A fluid-dispensing valve for dispensing pressurized fluid from a chamber employs a spring plate adjacent to the aperture. The spring plate includes a peripheral rim extending about the aperture, a sealing member abutting the aperture, and a plurality of springs extending from the peripheral rim to the sealing member. These springs bias the sealing member to close the aperture when the fluid pressure is less than a predetermined limit and allow the sealing member to open the aperture when the fluid pressure exceeds the limit.

RELATED APPLICATION

The present application is based on and claims priority to the Applicants' U.S. Provisional Patent Application 61/095,873, entitled “Fluid Dispensing Valve With A Spring Plate,” filed on Sep. 10, 2008.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to the field of valves for dispensing fluids. More specifically, the present invention discloses a fluid dispensing valve having a spring plate to prevent drips.

2. Background of the Invention

The present invention addresses the problem of dispensing fluid materials at a high rate of speed accurately and without drips. Current dispensing technologies for fluid materials have an inherent problem of dripping when not in use unless some means is used to stop material flow. Conventional methods to stop fluid dripping involve mechanical means that are operated by pneumatics or electronics to open and close a material pathway. This method when activated imparts a delay at the beginning of the dispense process due to the retraction of the pathway sealing device as it pulls material into the dispense nozzle or material pathway. Additional dispense time is required to replenish the material that moved with the sealing device.

Subsequently, when conventional methods are employed to stop material flow, an extra quantity of material equivalent to the gap the sealing device must occupy is ejected, which can result in an undesirable bubble in the dispense path. To control the range of movement (i.e., stroke) in such conventional methods, a mechanical adjustment and setup are required that should be done with care and periodically checked to ensure dispense quantity.

Other conventional methods to control fluid material flow involve the induction of vacuum or ensuring the dispense pathway is a sealed environment. These methods are not quick to react as they require a pressurization and depressurization of the material pathway or reservoir that may change in volume over the life of the material reservoir. This pressurization step takes valuable dispense time and also can yield inconsistent results when the controlling volume increases as the level in the material reservoir decreases.

In contrast, the present invention substantially eliminates adjustment issues as it is a self-contained, consumable device requiring no adjustment. Dispense delay and excess material at the finish are all but eliminated.

SUMMARY OF THE INVENTION

This invention provides a valve for dispensing a fluid material having a spring plate to prevent drips. The spring plate has a sealing member suspended by springs that bias the sealing member to close the aperture when the fluid pressure is less than a predetermined limit, but allow the sealing member to move away from the aperture and permit fluid flow when this pressure limit is exceeded.

These and other advantages, features, and objects of the present invention will be more readily understood in view of the following detailed description and the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention can be more readily understood in conjunction with the accompanying drawings, in which:

FIG. 1 is an exploded perspective view of the aperture plate 20 and spring plate 30.

FIG. 2 is a side elevational view of the valve assembly.

FIG. 3 is a cross-sectional view of the valve assembly.

FIG. 4 is a detail cross-sectional view of the lower portion of the valve assembly.

DETAILED DESCRIPTION OF THE INVENTION

Turning to FIG. 1, an exploded perspective view is provided showing one embodiment of an aperture plate 20 and spring plate 30 employed in the present invention. FIGS. 2 and 3 are side elevational and cross-sectional views, respectively, of a valve assembly 10 incorporating the aperture plate 20 and spring plate 30. A detail cross-sectional view of the lower portion of the valve assembly 10 is illustrated in FIG. 4.

The other major components of the valve assembly 10 are discussed below. A feed tube 12 receives fluid from a reservoir and transmits fluid into the chamber 15 of the valve assembly 10. The fluid in the chamber 15 is pressurized by rotation of an auger screw 14 in the embodiment shown in the accompanying drawings. However, other types of pumps or pressure sources could be readily substituted. For example, the fluid in the chamber 15 could be pressurized by pneumatically-generated or motor-generated motion of a piston, or other mechanically or pneumatically-generated means. The pressurized fluid can be delivered from the chamber 15 via a needle 18.

As shown in FIG. 1, the aperture plate 20 can be a flat, rigid disk with an aperture 22 extending through the plate 20 for dispensing fluid from the chamber 15. The size of the aperture 22 can vary depending on the viscosity of the fluid.

The spring plate 30 is mounted immediately downstream from the aperture plate 20. Preferably, the spring plate 30 is directly below and abutting the aperture plate 20, as shown in FIGS. 3 and 4. In this embodiment, the spring plate 30 has a peripheral rim 32, a sealing member 36 that is aligned to seal the aperture 22 in the aperture plate 20, and a plurality of springs 34 suspending the sealing member 36 from the peripheral rim 32. As depicted in FIG. 1, the sealing member 36 can be a flat disk having a diameter large enough to seal the aperture 22 in the aperture disk 20. In this embodiment, the springs 34 and peripheral rim 32 are also substantially flat or planar. The peripheral rim 32 can be a flat ring that extends about the aperture 22.

The springs 34 serve to suspend the sealing member 36 from the peripheral rim 32 of the spring plate 30, but also to bias the sealing member 36 against the aperture 22 in the aperture plate 20. Preferably, the springs 34 extend in a radial pattern between the sealing member 36 and the peripheral rim 32. For example, the springs 34 can be a web of flat, U-shaped members allowing a range of elastic deformation in response to fluid pressure on the sealing member 36 exerted through the aperture 22 in the aperture disk 20. As shown, the entire spring plate 30 can be formed as a single, flat piece of material, such as sheet metal or plastic. Other types and configurations of elastically-deformable materials could be used as springs. For example, the springs 34 could be S-shaped, curved or a zig-zag shape. Coil springs could also be used.

In operation, the springs 34 bias the sealing member 36 upward against the aperture 22 in the plane of the spring plate 30. As long as the fluid pressure within the chamber 15 remains below a predetermined limit (i.e., a threshold value), the springs 34 exert sufficient force to hold the sealing member 36 against the aperture 22, and thereby seal the aperture 22 to prevent fluid flow through the aperture 22. However, if fluid pressure increases beyond this limit, the pressure exerted on the sealing member 36 is sufficient to elastically deform the springs 34 downward out of the plane of the spring plate 30 and push the sealing member 36 downward and away from the aperture 22 in the aperture plate 20. This unseals the aperture 22 and allows fluid flow through the aperture 22.

In other words, by using a combination of a stiff, non-flexing aperture plate 20 and a flexible, spring plate 30, a dynamic membrane is created that allows a fluid to pass when sufficient pressure is applied on the inlet side of the aperture 22. Pressure exceeding some threshold value will separate the plates 20, 30 allowing the fluid to pass. As long as the pressure is maintained fluid will continue to flow. Reducing the fluid pressure causes the plates 20, 30 to return to their normally closed state which stops fluid flow. The opening and closing action follows the pressure curve generated by the pressure source for the valve assembly 10 and has a specific pressure required to open and close. This specific pressure results in an even flow of material that eliminates excess or insufficient material.

The size of the aperture 22 should be specifically selected for physical properties of the fluid being dispensed and the operating parameters of the valve assembly, such as the range of fluid pressures. The aperture 22 size controls the fluid pressure exerted on the spring plate 30. If the aperture 22 is too large the fluid column will have enough pressure to overcome the spring plate sealing force and the system may drip. Similarly, the thickness and physical properties of the springs 34 and the dimensions of the sealing member 36 should also be specifically selected in light of the fluid properties and operating parameters. These design parameters can accommodate various levels of fluid fillers, viscosities and the pressure of the fluid column.

In the embodiment shown in FIGS. 2-4, the lower portion of the valve assembly 10 can be removed by unthreading a nut 16. This provides ready access to the chamber 15 and internal components of the valve assembly. The aperture plate 20 and spring plate 30 are also readily removable and can be quickly replaced. As shown most clearly in FIG. 4, the aperture plate 20 and spring plate 30 can be dropped into this lower portion of the valve assembly housing, which is then threaded with the nut 16 onto the upper portion of the valve assembly 10.

It should be noted that the aperture and spring plates 20, 30 are positioned between the chamber 15 of the valve assembly 10 and the outlet (i.e., needle 18. This configuration minimizes the distance from the fluid to travel from the pressure generator to the exit at the needle 18 orifice, which serves to minimize dispense time and increase the accuracy of the quantity of fluid dispensed.

The previous discussion and the drawings involve an embodiment of the present invention in which the aperture and spring plates 20, 30 are completely separate components. It should be understood that these components could be combined into one piece to simplify assembly and replacement. For example, the peripheral rim 32 of the spring plate 30 could be bonded or attached to the underside of the aperture plate 20.

The above disclosure sets forth a number of embodiments of the present invention described in detail with respect to the accompanying drawings. Those skilled in this art will appreciate that various changes, modifications, other structural arrangements, and other embodiments could be practiced under the teachings of the present invention without departing from the scope of this invention as set forth in the following claims. 

1. A fluid-dispensing valve comprising: a chamber containing a fluid; an aperture for dispensing pressurized fluid from the chamber; and a spring plate adjacent to the aperture having: (a) a peripheral rim extending about the aperture; (b) a sealing member abutting the aperture; and (c) a plurality of springs extending from the peripheral rim to the sealing member, said springs biasing the sealing member to close the aperture when the fluid pressure is less than a predetermined limit and allowing the sealing member to open the aperture when the fluid pressure exceeds the limit.
 2. The fluid-dispensing valve of claim 1 wherein the springs extend in a radial pattern from the sealing member to the peripheral rim.
 3. The fluid-dispensing valve of claim 1 further comprising an aperture plate containing the aperture, and wherein the spring plate abuts the aperture plate.
 4. The fluid-dispensing valve of claim 1 wherein the springs comprise a flat curved shape.
 5. The fluid-dispensing valve of claim 1 wherein the springs comprise a web of U-shaped members extending between the sealing member and the peripheral rim allowing a range of elastic deformation in response to fluid pressure on the sealing member.
 6. The fluid-dispensing valve of claim 1 wherein the sealing member is substantially planar.
 7. The fluid-dispensing valve of claim 1 wherein the spring plate is substantially planar when the aperture is closed, and wherein the springs elastically deform to move the sealing member away from the aperture in the open position.
 8. The fluid-dispensing valve of claim 1 wherein the peripheral rim comprises a flat ring.
 9. A fluid-dispensing valve comprising: a chamber containing a fluid; an aperture plate having an aperture for dispensing pressurized fluid from the chamber; and a substantially planar spring plate abutting the aperture plate, said spring plate having: (a) a peripheral rim extending about the aperture; (b) a sealing member abutting the aperture; and (c) a plurality of flat curved springs suspending the sealing member from the peripheral rim, said springs biasing the sealing member against the aperture to close the aperture when the fluid pressure is less than a predetermined limit, and deforming to move the sealing member away from the aperture to thereby open the aperture when the fluid pressure exceeds the limit.
 10. The fluid-dispensing valve of claim 9 wherein the springs extend in a radial pattern from the sealing member to the peripheral rim.
 11. The fluid-dispensing valve of claim 9 wherein the springs comprise a web of U-shaped members extending between the sealing member and the peripheral rim allowing a range of elastic deformation in response to fluid pressure on the sealing member.
 12. The fluid-dispensing valve of claim 9 wherein the sealing member is substantially planar.
 13. The fluid-dispensing valve of claim 9 wherein the peripheral rim comprises a flat ring. 